Function read_value_ref Copy item path

Attempts to read the data from the given reader until either a complete MessagePack value decoded or an error detected.

Returns either a non-owning ValueRef, which borrows the buffer from the given reader or an error.

The reader should meet the requirement of a special BorrowRead trait, which allows to mutate itself but permits to mutate the buffer it contains. It allows to perform a completely zero-copy reading without a data loss fear in case of an error.

Currently only two types fit in this requirement: &[u8] and Cursor<&[u8]>. Using Cursor is helpful, when you need to know how exactly many bytes the decoded ValueRef consumes. A Vec<u8> type doesn’t fit in the BorrowRead requirement, because its mut reference can mutate the underlying buffer - use Vec::as_slice() if you need to decode a value from the vector.

§Errors

Returns an Error value if unable to continue the decoding operation either because of read failure or any other circumstances. See Error documentation for more information.

This function enforces a maximum recursion depth of MAX_DEPTH and returns Error::DepthLimitExceeded if the maximum is hit. If you run into stack overflows despite this, use read_value_ref_with_max_depth with a custom maximum depth.

§Examples

use rmpv::ValueRef;
use rmpv::decode::read_value_ref;

let buf = [0xaa, 0x6c, 0x65, 0x20, 0x6d, 0x65, 0x73, 0x73, 0x61, 0x67, 0x65];
let mut rd = &buf[..];

assert_eq!(ValueRef::from("le message"), read_value_ref(&mut rd).unwrap());